1. Field of the Invention
The present invention relates to a development device and an image forming apparatus.
2. Description of Related Art
In a related-art image forming apparatus such as a printer, a photocopier, a facsimile machine, and a multi-functional peripheral employing an electrophotographic method, for example, the related-art printer performs processes of charging, exposing, developing, transferring, cleaning, and discharging in a vicinity of a photosensitive drum. A toner image formed on the photosensitive drum is transferred to and fixed on a sheet serving as a medium.
In such a related-art printer, the developing process is performed by a development device that includes a development roller developing an electrostatic latent image formed on the photosensitive drum by adhesion of toner and a toner supply roller not only supplying the toner to the development roller and but also scraping residual toner remained on the development roller after the developing process. Japanese Un-examined Patent Application Publication No. 2002-108090 discloses such a toner supply roller to which voltage is applied so as to supply the toner to the development roller.
In such a related-art development device, since an electric field is formed by the voltage so as to adhere charged toner to the development roller, the residual toner remained on the development roller is not adequately scraped. Consequently, the residual toner remained on the development roller in a previous developing process is used for a next developing process, causing generation of a residual image on the sheet. Such a residual image causes deterioration of an image quality.
It is an object of the present invention to provide a development device and an image forming apparatus capable of reducing the residual image on the medium and enhancing the image quality.